“This will be a big project and we will need leaders who are excited to see the new direction through.”

He did not give a reason for leaving, but Mr Zuckerberg insisted that he had “been discussing… his desire to do something else” for several years.

Mr Daniels, meanwhile, started as head of Whatsapp after five years of running Internet.org, an initiative to boost internet connectivity around the world.

He will be replaced by Will Cathcart, who currently heads up Facebook’s mobile app. Fidji Simo, who ran the app while Mr Cathcart was away on paternity leave, will take on his role.

No replacement has been announced for Mr Cox.

Facebook has lost several top executives during the last two years, including its general counsel, chief security officer, and co-founders of WhatsApp, Instagram and Oculus, a virtual reality firm it bought in 2014.

Facebook has been sharply criticised in the past over lack of user privacy and the spread of offensive content and misinformation.